Add GitHub actions for automated NPM release

Build, tests, and release via GitHub.
NPM_TOKEN is stored as a secret, and scoped to @cloudflare/voprf-ts.

.github/workflows/release.yml

@@ -0,0 +1,35 @@
+name: Release
+
+on:
+  release:
+    types:
+      - published
+
+jobs:
+  release:
+    if: ${{ github.repository_owner == 'cloudflare' }}
+    name: Publishing to npmjs registry
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checking out
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Use Node.js 20
+        uses: actions/setup-node@v3
+        with:
+          node-version: 20
+          cache: 'npm'
+
+      - name: Install NPM dependencies
+        run: npm ci
+
+      - name: Check build
+        run: npm run build
+
+      - name: Publish to npmjs
+        run: npm publish
+        env:
+          # To create a new token, go to https://www.npmjs.com/settings/<user>/tokens/, generate a "Granular Access Token" scoped to @cloudflare/voprf-ts, and update NPM_TOKEN GitHub secret
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/tests.yml

@@ -0,0 +1,41 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  testing:
+    name: Testing on Node v${{ matrix.node }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node: [20, 18]
+    steps:
+      - name: Checking out
+        uses: actions/checkout@v3
+
+      - name: Use Node.js v${{ matrix.node }}
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node }}
+          cache: 'npm'
+
+      - name: Install NPM dependencies
+        run: npm ci
+
+      - name: Check lint
+        run: npm run lint
+
+      - name: Check build
+        run: npm run build
+
+      - name: Run NPM tests
+        run: npm test
+
+      - name: Check examples
+        run: npm run examples